1. Thực hiện phép tính:
a) \(\frac{1-3x}{2x}+\frac{3x-2}{2x-1}+\frac{3x-2}{2x-4}\)
b) \(\frac{1}{x^2+6x+y}+\frac{1}{6x-x^2-9}+\frac{x}{x^2-9}\)
c) \(\frac{x^2+2}{x^3-1}+\frac{2}{x^2+x+1}+\frac{1}{1-x}\)
d) \(\frac{x}{x-2y}+\frac{x}{x+2y}+\frac{4xy}{4y^2-x^2}\)